CVE-2024-46829

What it actually does

rt_mutex_handle_deadlock holds rt_mutex::wait_lock while entering schedule() in the deadlock path, violating atomic context rules and emitting scheduling-in-atomic warnings.

Why it matters to the business

Linux systems may experience kernel warnings or brief instability during rt_mutex deadlock scenarios, increasing operational risk for real-time or latency-sensitive workloads until patched.

How an attack unfolds

An attacker triggers rt_mutex contention leading to the deadlock branch inside rt_mutex_handle_deadlock; the held wait_lock then causes the kernel to schedule while atomic, surfacing the latent bug.

How to fix it

Upgrade the Linux kernel to a version containing commit 1860e379875dfe7271c649058aeddffe5afd9d0d or later; rebuild and reboot affected systems.

How to confirm the fix worked

Verify the running kernel git commit or version string contains 1860e379875dfe7271c649058aeddffe5afd9d0d; confirm absence of scheduling-in-atomic warnings referencing rt_mutex after applying the update.

Typical attack path

1. Create contention on an rt_mutex from multiple threads or processes
2. Force a deadlock condition that invokes rt_mutex_handle_deadlock with wait_lock held
3. Enter the endless scheduling loop without releasing the lock

How to detect it

Search kernel logs and dmesg for 'scheduling while atomic' or 'BUG: scheduling while atomic' messages that reference rt_mutex_handle_deadlock or wait_lock; inspect crash dumps for rt_mutex state.

• scheduling while atomic
• rt_mutex_handle_deadlock
• wait_lock

What your security team should do

• Prioritize kernel updates containing the referenced commit for all production systems
• Monitor kernel logs for 'scheduling while atomic' warnings tied to rt_mutex
• Test patched kernels in staging environments before broad deployment